The story features ubiquitous creatures called Mushithat often display what appear a supernaturalpowers. It is implied that there are many more lifeforms more primitive than "normal" living things such as animals, plants, fungi and bacteria, and Mushi is the most primitive of all. Due to their ethereal nature most humans are incapable of perceiving Mushi and are oblivious to their existence, but there are a few who possess the ability to see and interact with Mushi. One such person is Ginko, the main character of the series. He employs himself as a Mushi master, traveling from place to place to research Mushi and aid people suffering from problems caused by them. The series is an episodic anthology in which the only common elements among episodes are Ginko and the various types of Mushi. There is no overarching plotline.